Chicken massacre this morning 😔

[Cheshire Chickens]

This morning we woke up to the chickens crying out. By the time we got out to the yard 4 of our 5 chickens were dead They all were missing their heads… We have an automatic chicken door that is set to open at 7am (when the sun comes up here). I’m now thinking this was too early. We have had free range chickens for about a year now with no issues, but I was letting them out myself at around 9-10am. This is our first loss so we are feeling all the emotions. Thinking maybe it could have been a hawk or owl? Doesn’t appear to be any predator foot prints in the mud. Any insight or similar experiences? Thanks everyone.
Also, we are thinking about getting mini goats to protect the new chickens in the future? Do they really protect well or is this just a myth? Thanks!

Oh I so feel for you 7am may be a little early, where are you?
I’m in the UK similarly had our first fox attack yesterday - kept chickens for coming on 5 years now. This is the first summer I’ve had the auto door (set for 6am, light at 5am here in June/july) I’ve got a camera set up so I keep an eye on them as they come out of the henhouse into their unsecured run. They usually go wandering out free range around 7am - sometime between 8am and 10am fox I think has taken Bluebell. Stupidly incident think they’d predate them in the day - but reading lots of articles and experiences foxes will attack at anytime day or night.
I got complacent and the fox took advantage. Sorry Bluebell Just a handful of feathers and my other 2 chickens very spooked.
Needless to say no more unsupervised free ranging, and I feel dreadful that I put her in harms way and let her down.